Charge forming device for internal combustion engines



y 12, 1964 B. c. PHILLIPS CHARGE FORMING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed June 2, 1958 2 Sheets-Sheet 1 INVENTOR 2 .EHNARU EPJHLLIPS.

TIE-3 B- C. PHILLIPS- May 12, 1964 CHARGE FORMING DEVICE FOR INTERNAL COMBUSTION ENGINES 2 SheetS -Sheet 2 Filed June 2, 1958 r M M INVENTORZ 3212mm] E'.PHILLIP5.

MAQTW United States Patent Ofifice 3,133,129 Patented May 12, 1964 3,133,129 CHARGE FORMING DEVICE FUR INTERNAL CGMEUSTION ENGINES Bernard C. Phillips, Toledo, Ohio, assignor to The Tiliotson Manufacturing Company, Toledo, ()hio, a corporation of Uhio Filed June 2, 195a, Ser. No. 739,414 6 Ciaims. e1. 261-42) This invention relates to charge forming apparatus or device for supplying a mixture of fuel and air to an internal combustion engine and more especially to a charge forming apparatus embodying a flexible diaphragm adapted to be controlled by aspiration or reduced pressure in a mixing passage for automatically regulating the delivery of fuel from a supply into a reservoir chamber in the charge forming device from which the fuel is conveyed to the mixing passage.

The conventional type of charge forming device embodying a float-actuated fuel control valve arrangement is wholly unsuitable for use with internal combustion engines which are to be operated in positions of tilt or extreme angular positions. Furthermore carburetors or charge forming devices wherein the fuel flow control valve is float-actuated are extremely sensitive to vibrations and hence are prone to deliver an oversupply of fuel when subjected to vibrations during operation.

The present invention embraces a carburetor or charge forming device for delivering or feeding a fuel and air mixture to an internal combustion engine which is effective in substantial positions of tilt to maintain proper delivery of fuel to an engine.

Another object of the invention is the provision of a charge forming device or carburetor of simplified character embodying a diaphragm arranged to be influenced solely by pressures in the mixing passage for controlling the delivery of fuel into the mixing passage.

Another object of the invention is the provision of a diaphragm-type of charge forming device wherein fuel is delivered into the mixing passage through a single outlet and solely by aspiration established through engine operation and with a minimum of differential pressure whereby fuel is effectively delivered into the mixing passage under severe conditions of vibration, substantial tilting of the charge forming device and under a wide range of fuel supply pressures.

Another object of the invention is the provision of a simplified, comparatively small diaphragm-type carbu retor having a single fuel delivery orifice from a fuel chamber into the mixing passage whereby the charge forming device has particular utility with internal combustion engines especially of the two cycle type adaptable for operation at substantially constant or governed speeds.

Another object of the invention is the provision of a comparatively small diaphragm-type charge forming device which may be inexpensively manufactured and which finds utility for particular uses such as with engines for operating stone hammers, combustion heaters for vehicles and particularly truck vehicles, special military equip- 'ment, engines for chain saws, portable power drilling units, lightweight generator units and tions.

Another object of the invention is the provision of a small, compact diaphragm-type carburetor wherein the number of components have been reduced to a minimum whereby a charge forming device of this character may be economically produced.

Another object of the invention is the provision of a compact diaphragm carburetor which during operation is substantially immune to the adverse effects of vibration and which will deliver the proper flow of fuel into the mixing passage under various operating conditions and similar applicawherein etficient atomization and distribution of metered fuel into the mixing passage is attained with a minimum of movable components.

Another object of the invention is the provision of a diaphragm-type of charge forming device wherein fuel is delivered into a mixing passage through a single orifice and solely by aspiration established through engine operation and which may be brought into and maintained in operation under a minimum of reduced pressure effective to establish fuel delivery to the mixing passage.

Another object of the invention is the provision of a charge forming device embodying a fuel flow control ball valve which is directly controlled by a diaphragm which is extremely sensitive to pressure variations whereby an effective and critical control is maintained over fuel flow into the charge forming device.

Another object of the invention is the provision of a carburetor construction in which the body member may be fashioned of moldable resins which are immune to the deleterious effects or deterioration from contact with hydrocarbon fuels whereby the carburetor body may be manufactured economically and with complete interchangeability of components.

Another object of the invention is the provision of a simplified carburetor of the diaphragm-type wherein the body component may be molded of suitable material and fashioned or configurated wherein a minimum of machining operations is required and wherein the passages or ducts in the carburetor body may be varied in size to accommodate one size of carburetor body to various sizes of engines or combustion devices.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a side elevational view of a form of charge forming device of the invention with air cleaner attached;

FIGURE 2 is a top plan view of the carburetor construction illustrated in FIGURE 1; H

FIGURE 3 is a bottom plan view of the arrangement shown in FIGURE 1 with the. diaphragm, retaining plate and air cleaner removed;

FIGURE 4 is a longitudinal detail sectional view taken substantially on the line 44 of FIGURE 2;

FIGURE 5 is a detail sectional view taken substantially on the line 5-5 of FIGURE 2;

FIGURE 6 is a detail sectional view taken substantially on the line 6-6 of FIGURE 2;

in forming mixture charges for an internal combustion engine of the two cycle type, it is to be understood that the charge forming device of the invention may be utilized with four cycle internal combustion engines.

Referring to the drawings in detail and initially to the form of the invention illustrated in FIGURES 1 'through 6, the charge forming device or carburetor is 70.

inclusive of a body or body member 10 which may be a die casting fashioned or zinc or alloys of zinc and aluminum or other constituents or may be fashioned or molded of resinous plastic which is unaffected by hydrocarbon fuels.

The body 18 is formed with a mixing passage 12 which preferably includes a Venturi configuration 14 into which liquid fuel is delivered for admixing with air admitted through an air inlet 16. While a Venturi embodied in the mixing passage is preferred in order to obtain high air velocity through the mixing passage, it is to be understood that the carburetor may be utilized with small low horsepower engines and heaters and in such instances the Venturi may be dispensed with and the walls of the mixing passage of cylindrical shape.

A disk-type valve 18 providing a throttle control for regulating the rate of admission of the mixture into the engine may be mounted upon a supporting shaft 20 which is journaled in a bore formed in a boss portion 22 of the body, the shaft 20 extending into a bore 24 formed in the carburetor body as particularly illustrated in FIG- URE 4, the disk 18 being secured to the shaft 20 by means of a screw 25. An operating arm 26 is secured to a tenon portion formed on the shaft 28 extending exteriorly of the boss 22. The arm 26 may be provided with a fitting 28 for manipulating the throttle 18, the fitting being adapted for connection with a flexible wire control (not shown) whereby the throttle maybe manipulated at a position remote from the carburetor.

The carburetor body is provided with a flange 30 which is adapted to be secured to a boss portion 32 formed on the wall of a crankcase 25 of an engine of the two cycle type or to an intake manifold of an engine of the four cycle type. The flange 30 is secured'to the boss 32 by means of bolts 34. An air cleaner 36 may be connected with the air inlet 16 as shown in FIGURES 1 and 2.

The body 10 of the charge forming device is formed with shallow fuel chamber or passage 38 of minimum depth to reduce to a minimum the amount in the chamber 38. A flexible member, diaphragm or membrane 4%) forms one Wall of the shallow chamber 38 as shown in FIGURES 4 through 6. An annular gasket 43 is disposed adjacent one face of the flexible diaphragm 40, preferably between the diaphragm and the body 10, to effect a liquid tight seal between the body and the diaphragm. A cover plate 42, which may be formed of sheet metal or of molded resinous plastic or the like, has a peripheral planar portion 44. The planar portion 44, the peripheral region of the diaphragm 40 and the gasket 41 are provided with aligned openings to accommodate securing screws 46 which are threaded into openings 47 formed in the body 10, one of the securing screws being illustrated in FIGURE 5 extending into a threaded opening in the body 10.

The cover or closure plate 42, as shown in FIGURES 4 through 6, is fashioned or formed with a depressed central region or portion providing a space 48 to accommodate movements of the diaphragm 40, the space 48 being vented to the atmosphere by means of an opening 59. The diaphragm 48 is preferably made of very thin, flexible cloth, as for example, nylon fabric impregnated with a suitable coating material to render the diaphragm impervious, or the diaphragm may be made of synthetic rubber or similar material of a character which is unaffected by contact with hydrocarbon fuels.

In the carburetor of the invention, the fuel is delivered into the region of the choke band 15 or region of maximum restriction of the Venturi 14 to attain maximum aspiration by the high velocity air flow through the Venturi, the fuel being delivered through an outlet or orifice 54 which is in communication with the fuel chamber or reservoir 38 in a manner and through passages hereinafter described.

The charge forming apparatus or carburetor is inclusive of means operatively associated with and adapted to be controlled by the diaphragm 40 for regulating or controlling the flow of fuel from a supply into the shallow fuel chamber or passage 38. The diaphragm control arrangement for a fuel inlet valve means is particularly shown in detail in FIGURE 5. The body 10, at the region defining a wall of the chamber 38, is formed with an elongated recess 56. shaped to accommodate a lever or lever member 58 which is pivotally supported upon a pin 68 mounted in suitable bores formed in the body 10.

It should be noted that the fuel chamber or passage 38 is not vented to the atmosphere and fuel from the chamber is delivered into the mixing passage 12 solely by engine aspiration through the single orifice or fuel outlet 54. By reason of the fact that fuel is delivered into the mixing passage solely by aspiration effect of differential or subatmospheric pressure in the mixing passage acting upon the fuel chamber 38, there is no predetermined or defined static fuel level in the chamber 38 as this may vary by reason of air or gas bubbles in the fuel supply or when the carburetor is tilted.

The diaphragm 46 is preferably reinforced throughout a circular central region thereof by means of a thin'metal disk 62 which is secured to the diaphragm by means of a headed member or rivet 64, the head portion 65 thereof being in contact with the longer arm of the lever 58 as shown in FIGURE 5. As fuel is delivered into the mixing passage through the orifice or outlet 54 under the influence of reduced pressure communicated through fuel passages or ducts hereinafter described with the fuel chamber 38, the flow or delivery of fuel into the mixing passage depletes the supply in the passage or chamber 38, further decreasing the pressure in the chamber 38 which flexes the diaphragm effecting movement of the lever member 58.

The body 19 is provided with a boss portion 68 having a threaded opening 70 adapted to accommodate a fitting 72 which is connected by means of a pipe or tube 74 with a fuel tank (not shown) or other supply or source of fuel to be delivered into the chamber 38. The threaded opening .79 is formed with a continuation opening 76 which is in communication with a passage 78 as shown in FIGURE 5. Disposed at the terminus of the passage 78 is a valve seat 79 formed of resilient synthetic rubber or similar material, the member 79 being formed with a port 80. An elongated valve or valve member 82 is disposed between the short arm 84 of the lever 58 and the seat region of the resilient valve seat 78.

In the illustrated embodiment, the body portion of the valve member 82 is of triangular cross-section to facilitate flow of fuel along the facets of the triangular cross-section of the valve but the same may be of other cross-sectional configuration, such as a Maltese cross shape. The upper extremity of the valve member 82 adapted for seating against the member is of cone-shaped configuration as shown at 86 to seat against the circular edge region of member 79 defining the point 80. A fitting 88 is threaded into a suitable threaded bore axially aligned with the passage 78 :and functions :to retain the valve seat 79 in proper position as shown in FIGURE 5. The lower end of the valve member 82 contacts or restsdirectly upon the shout arm 84 of the lever '58. The lever 58 is normally biased toward a position to cause the valve 82 to close the port 80, the bias being in a direction to rotate the lever member 58 in -a clockwise direction as viewed in FIGURE 5. An expansive coil spring 90 contained in a bore 92 formed in the body being utilized as the biasing means, one end of the spring 90 being bottomed in the bore 92 and the other end engaging the long arm of the lever 58 at a region proximate to the fulcrum pin 60 as shown in FIGURE 5. The spring 9.0 is fashioned to exent the proper pressure upon the valve member 82 to prevent ingress of fuel through the port in the valve member under the fuel pressures normally provided by the gravity head of fuel in the fuel tank 1 which is usually positioned slightly above the carburetor. It is to be understood however that while the carburetor the invention is particularly adapted for use where the I v 6 is provided with a bore 100 accommodating The valve member 102 is formed with fuel flows to the carburetor by gravity, the fitting 72 may be connected with a suitable fuel pump if desired for supplying fuel under comparatively low pressure.

It should be noted that the valve portion 86 is faced toward the incoming fuel entering through the duct 78 so that the effective hydrostatic pressure against the valve portion 86 is determined by the area of the port '80 in the valve seat 79. Thus by making the port 80 relatively small, a comparatively low pressure is exerted against the valve portion 86. Hence a minor or relatively low differential pressure is effective to move or flex the diaphragm 40 and through the medium of the lever 58 facilitates movement of the valve portion 86 away from the seat 79 to admit fuel through the port 80 into the passage or chamber 38.

The sensitiveness of this mechanism may be varied or regulated by changing the effective pressure of the spring 90 acting against the lever 58. Thus where higher fuel pressures are existent in the inlet duct 76, the spring 90 may be fashioned or dimensioned to exert a greater pressure upon the lever 58 to maintain the valve portion 86 normally in a seated or valve closing position when no aspiration is effective in the chamber 3-8 to actuate the diaphragm 40.

Through this arrangement the balance of forces effective to maintain the valve 86 in closed position is sufii ciently low so that a minute reduction in pressure in the fuel chamber 3-8 under the influence of the aspiration effect in the mixing passage set up by engine operation brings the fuel orifice 54 into operation to discharge fuel into the Venturi 14 and opens the valve 86 to admit fuel to the chamber 38. It has been found that a differential or reduced pressure in the chamber 38 equal to that required to support a column of water about three-eighths of an inch in heighth is sufficient to initiate fuel delivery through the orifice or outlet 54 into the mixing passage.

In such arrangement it has been found that for most installations a choke valve is not required. However it should be noted in FIGURE 2 that the body is formed with boss portions 92 which may be bored to accommo date a rotatable shaft 93 which supports a choke valve of the disk-type 95, the shaft 93 and the choke valve 95 being shown in broken lines in FIGURE 2. Thus the use of a choke valve is optional depending upon the characteristics of the internal combustion engine or a combustion heater with which the carburetor or charge forming device may be used.

A simple yet effective duct system is provided for conveying or delivering fuel (from the chamber or passage 38 to the orifice or outlet 54 into the Venturi 14 of the mixing passage. Such arrangement is illustrated in FIG- URES 3, 4 and 6. A passage or duct 94 is drilled into the body aligned with the fuel discharge orifice 54 as shown in FIGURE 6 and the entrance the entrance region of the duct 94.

A boss portion 98 of the body 10 as shown in FIGURE an adjustable valve body or member 102 which is formed with a tapered or needle valve portion 104 projecting into a duct 106 which is in communication with the duct 94. a threaded portion 108 which is threaded into a threaded portion of the bore 100.

A resilient sealing member or O-ring 110 formed of synthetic rubber surrounds a portion 112 of the valve member 102 to prevent leakage of fuel to exterior of the carburetor body 10. A head portion 114 of member 102 extends exteriorly of the boss 98 and is provided with a kerf 115 to accommodate a tool for adjusting the position of the needle portion 104 of valve member 102 to meter, regulate or control fuel flow to the discharge outlet or orifice 54 thorugh the passage or duct 106.

As shown in broken lines in FIGURES 3 and 4, a passage or duct 118 establishes communication between the to passage 94 sealed by a member 96 such as a lead pellet pressed into bore and the recess 56. Thus fuel flows from the chamber or passage 38 through the duct 118 into the bore 100 past the needle valve 104 through duct 106 into the duct or passage 94 and through the outlet or orifice 54 into the choke band or restricted portion 15' of the mixing passage 12 into the engine aspirated air stream flowing through the mixing passage. By adjusting the valve member 104 the rate of fuel flow discharged from the orifice 54 may be accurately controlled.

The carburetor of the present invention is particularly usable with engines which operate at substantially constant speeds or within a defined or governed speed range. By adjusting the throttle 18 the speed of the engine may be controlled within the desired operable range and when the throttle valve 18 is nearly closed, the engine will operate at idle speed through the discharge of fuel through the single orifice 54. Such arrangement is operable as the chamber 38 is unvented to the atmosphere and due to the proximity of the chamber '38 to the mixing passage 12, a low aspiration and hence a very minor pressure differential will initiate and maintain delivery of fuel through the orifice 54.

While the arrangement of the invention is particularly adaptable for comparatively small or fractional horsepower engines, it has been found that the diameters of the various regions of the mixing passage may be varied to render the carburetor usable for various sizes of engines and for combustion heaters. Thus, for example, the most restricted portion or choke band 15 of the Venturi may be as small as three-sixteenths of an inch in diameter and may be increased to about seven-eighths of an inch in diameter dependent upon the engine with which the carburetor is used. Where the choke band area is modified, the diameter of that portion of the mixing passage containing the throttle 18 is also modified to accommodate a reduced or increased flow of mixture dependent upon the size of the engine with which the carburetor is used. Thus by modifying the size of the mixing passage, the carburetor may be readily adapted to different sized engines, from a single size of carburetor body construction. This permits volume production and hence a substantial reduction in the cost of carburetors of this character.

Through the use of a diaphragm controlled fuel inlet valve, the carburetor may be operated under severe vibrations, extreme tilting of its position such as that encountered in chain saws or lawnmowers and under a wide range of fuel inlet pressures. The carburetor of the invention is substantially immune to vibrations and hence it is rendered particularly adaptable for use in lawn mowers.

For most uses it is preferable to admit or bleed air into the fuel just prior to its discharge through the outlet or orifice 54 to provide an emulsion delivered into the mixing passage. An air bleed for performing this function is illustrated in FIGURES 3 and 4 and includes a bore or duct 120 opening into the mixing passage adjacent the entrance end of the Venturi 14 as shown in FIGURE 4. A metering passage or duct 122 connects the bore 120 with the bore or passage 94 and is of comparatively small size to meter or regulate the admission of a small amount of air from the inlet region 16 of the mixing passage through the metering duct 122 for mixing with the fuel in the duct or passage 94 prior to the delivery of the fuel through the outlet orifice or duct 54 into the mixing passage. The amount of air admitted to the fuel in the passage 94 may be varied or metered by modifying the size of the metering passage or duct 122. It is to be understood that the passage 120 does not function as a fuel discharge orifice but functions solely as an air bleed, the same being subjected to a reduced pressure zone of the inlet region of the mixing passage.

Where the carburetor of the invention is utilized for supplying a combustible mixture to combustion heaters such as those employed on trucks during the winter to avoid freezing of perishables,'the Venturi arrangement 14 may be dispensed with and mixing passage formed as a cylindrical bore in the body It). In such installations the air velocities are comparatively low and hence the area of the mixing passage is made comparatively small to attain sufficient aspiration by air flow to elfect reduced pressure in the chamber 38 sufficient to effect delivery of fuel into the mixing passage.

FIGURE 7 is illustrative of another form of valve means utilized to regulate or control the flow of fuel into the fuel chamber. In this form a valve member 130 in the form of a sphere or ball is utilized as a valve means for regulating the fuel flow into the chamber 38. In this arrangement the carburetor body is provided with a threaded bore 132 adapted to receive a cage or valve guiding member 134. The valve guiding member is formed with a shoulder which supports a valve seat member 138 of resilient material'such as synthetic rubber or resilient material which is not affected by hydrocarbon fuels. The hollow guide 134 is dimensioned to loosely accommodate the valve or ball member 139 in the manner illustrated in FIGURE 7. The fitting 134 is formed with a thin-walled portion 140 engaging a spacer or gasket 142 disposed above the valve seat member 138. The ball member or valve 130 directly contacts the short arm 84' of the lever 58' whereby movements of the lever 58 are transmitted directly to the ball valve 130 to control the fuel flow into the chamber 38'.

The ball member 130 is preferably made of moldable polyamide resin, commercially known as nylon which is of comparatively lightweight and has long wearing qualities so that a reliable means is provided for controlling the ingress of fuel into the chamber 38'. Such arrangement as illustrated in FIGURE 7 may be inexpensively manufactured. The valve retaining or guiding cage or fitting 134 may be fashioned of metal or may be molded of polyamide resin or the like.

The carburetor may be provided with a fixed metering means in lieu of the adjustable metering needle valve 104. FIGURE 8 illustrates a portion of the carburetor of the character shown in FIGURE 4 with a fixed metering orifice. In this figure, the carburetor body 10", the Venturi 14", the lever 58", diaphragm 40", chamber 38", closure plate 42" and the fuel outlet passage 54" opening into the Venturi are of the same construction as the corresponding components shown in FIGURE 4. The fuel duct 150 as shown in FIGURE 8 is in communication with the fuel discharge passage 54". Fixed in a recess in the carburetor body at the terminus of the duct 159 is a member or disk 152 which is provided with a passage or opening 154- of a size to admit or meter fuel flow into the duct 150 and outlet or discharge passage 54". A fixed fuel metering means of this character may be utilized where the charge forming device is used with combustion heaters or with engines operating under substantially constant load and speed conditions.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. Charge forming apparatus including, in combination, a body member formed with a mixing passage, a shallow recess providing a fuel chamber formed in said body, a flexible diaphragm forming a Wall of the fuel chamber, a single fuel discharge orifice opening into the mixing passage, said orifice being connected by passage means with the fuel chamber, a lever fulcrumed on the body adapted to be actuated by flexure of the diaphragm, a fuel inlet passage formed in said body and adapted to receive fuel from a supply, a valve in said inlet passage arranged to be controlled by said lever, means in said passage means for metering the fuel flow from the chamber to the discharge orifice, resilient means biasing the lever ina direction closing the fuel inlet valve, said fuel chamber being unvented except through the mixing passage, and an air bleed channel formed in said body member between the passage means and the mixing passage and opening into said mixing passage at the air inlet region thereof for'conveying air into the fuel prior to its delivery through the orifice into the mixing passage.

2. Charge forming apparatus including, in combination, a body member formed with a mixing passage, a shallow recess providing a fuel chamber formed in said body, a flexible diaphragm forming a Wall of the chamber, a single fuel discharge outlet opening into the mixing passage, said orifice being connected by duct means with the fuel chamber, a lever fulcrumed on the body adapted to be actuated by flexure of the diaphragm, a fuel inlet passage formed in said body and adapted to receive fuel from a supply, a valve in said inlet passage arranged to be con trolled by said lever, resilient means biasing the lever in a direction closing the fuel inlet valve, said fuel chamber being unvented except through the mixing passage, and an air bleed channel between the duct means and the mixing passage and opening into said mixing passage at the air inlet region thereof for conveying air into the fuel prior to its delivery through the orifice into the mixing passage, said fuel chamber being arranged close to the mixing passage whereby fuel is delivered into the mixing passage by differential pressure equal to that required to support a column of Water about three-eighths of an inch in height.

3. Charge forming apparatus including, in combination, a body member formed with a mixing passage, said mixing passage being formed with a Venturi, a throttle valve in said mixing passage, a shallow recess providing a fuel chamber formed in said body, a flexible diaphragm forming a wall of the chamber, a single fuel discharge orifice opening into the Venturi of the mixing passage, said orifice being connected by duct means with the fuel chamber, a lever fulcrumed on the body adapted to be actuated by flexure of the diaphragm, a fuel inlet passage formed in said body and adapted to receive fuel from a supply, a valve in said inlet passage arranged to be actuated and controlled by said lever influenced by the diaphragm, metering means associated with said duct means for metering the fuel flow from the chamber to the discharge orifice, resilient means biasing the lever in a direction closing the fuel inletvalve, said fuel chamber being unvented except through the mixing passage, and an air bleed channel between the duct means and the mixing passage and opening into said mixing passage at the air inlet region of the Venturi for conveying air into the fuel prior to its delivery through the orifice into the mixing passage, said fuel chamber being arranged relative to the mixing passage whereby fuel is delivered into the mixing passage by differential pressure equal to that required to support a column of water about three-eighths of an inch in height.

4. Charge forming apparatus including, in combination, a body member formed with a mixing passage, said mixing passage, a shallow recess providing a fuel chamber formed in said body, a flexible diaphragm forming a wall of the chamber, a single fuel discharge orifice opening into the mixing passage, said orifice being connected by duct means with the fuel chamber, a lever fulcrumed on the body and having one arm in operative engagement with the diaphragm, a fuel inlet passage formed in said body and adapted to receive fuel from a supply, valve means for said fuel inlet passage including a valve seat member, a ball-shaped valve member formed of resin disposed between an arm of said lever and said seat member adapted to be controlled by movements of the diaphragm transmitted to the lever, said ball-shaped valve member being in engagement with the lever, resilient means biasing the lever in a direction to engage the valve member with the seat, an adjustable needle valve associated with said duct means for metering the fuel flow to the discharge orifice, said fuel chamber being unvented except through the mixing passage, and an air bleed chan- 9 nel in communication with the inlet region of the mixing passage and the duct means.

5. Charge forming apparatus including, in combination, a body member formed with a mixing passage, said mixing passage being formed with a Venturi, a throttle valve in said mixing passage, a shallow recess providing a fuel chamber formed in said body, a flexible diaphragm forming a Wall of the chamber, a single fuel discharge outlet opening into the mixing passage, said outlet being connected by duct means with the fuel chamber, a lever fulcnmied on the body arranged to be actuated by the diaphragm, a fuel inlet passage formed in said body adapted to convey fuel from a supply to said chamber, valve means associated With the inlet passage including a valve seat member of resilient material, a valve member disposed between an arm of the lever and said seat member, resilient means normally biasing the lever in a direction to engage the valve member in the seat, an adjustable needle valve associated with the duct means for metering the fuel flow to the discharge orifice, said fuel chamber being unvented except through the mixing passage, an air bleed channel in communication with the inlet region of the mixing passage and the duct means for conveying air into the fuel prior to its delivery through the outlet into the mixing passage, said fuel chamber being arranged close to the mixing passage whereby fuel is delivered into the mixing passage by difierential pressure equal to that required to support a column of water about three-eighths of an inch in height.

6. Charge forming apparatus including, in combination, a body member formed with a mixing passage, said mixing passage being formed with a Venturi, a throttle valve in said mixing passage, a shallow recess providing a fuel chamber formed in said body, a flexible diaphragm forming a wall of the chamber, a single fuel discharge outlet opening into the Venturi, said outlet being connected by duct means with the fuel chamber, a lever fulcrumed on the body arranged to be actuated by the diaphragm, a fuel inlet passage formed in said body adapted to convey fuel from a supply to said chamber, valve means associated with the inlet passage including a valve seat member of resilient material, a ball-shaped valve member formed of nonmetallic material disposed between an arm of the lever and said seat member, guide means for said valve member comprising a fitting secured to the body member, resilient means normally biasing the lever in a direction to engage the valve member in the seat, an adjustable needle valve associated with the duct means for metering the fuel flow to the discharge orifice, said fuel chamber being unvented except through the mixing passage, an air bleed channel formed in the body member in communication with the inlet region of the mixing passage and the duct means for conveying air into the fuel prior to its delivery through the outlet into the mixing passage, said fuel chamber being arranged close to the mixing passage whereby fuel is delivered into the mixing passage by differential pressure equal to that required to support a column of water about three-eighths of an inch in height.

References Cited in the file of this patent UNITED STATES PATENTS 1,002,646 Conrad Sept. 5, 1911 1,180,939 Ostenberg Apr. 25, 1916 1,890,994 Kerchner et a1 Dec. 13, 1932 2,372,532 Stewart Mar. 27, 1945 2,724,584 Armstrong Nov. 22, 1955 2,774,582 Bracke Dec. 18, 1956 2,796,243 McDuffie June 18, 1957 2,801,621 Anderson et a1. Aug. 6, 1957 2,823,905 Brown Feb. 18, 1958 2,827,272 Phillips Mar. 18, 1958 2,841,372 Phillips July 1, 1958 2,882,028 Seldon Apr. 14, 1959 

1. CHARGE FORMING APPARATUS INCLUDING, IN COMBINAITON, A BODY MEMBER FORMED WITH A MIXING PASSAGE, A SHALLOW RECESS PROVIDING A FUEL CHAMBER FORMED IN SAID BODY, A FLEXIBLE DIAPHRAGM FORMING A WALL OF THE FUEL CHAMBER, A SINGLE FUEL DISCHARGE ORIFICE OPENING INTO THE MIXING PASSAGE, SAID ORIFICE BEING CONNECTED BY PASSAGE MEANS WITH THE FUEL CHAMBER, A LEVEER FULCRUMED ON THE BODY ADAPTED TO BE ACTUATED BY FLEXURE OF THE DIAPHRAGM, A FUEL INLET PASSAGE FORMED IN SAID BODY AND ADAPTED TO RECEIVE FUEL FROM A SUPPLY, A VALVE IN SAID INLET PASSAGE ARRANGED TO BE CONTROLLED BY SAID LEVER,, MEANS IN SAID PASSAGE MEANS FOR METERING THE FUEL FLOW FROMTHE CHAMBER TO THE DISCHARGE ORIFICE, RESILIENT MEANS BIASING THE LEVER IN A DIRECITON CLOSING THE FUEL INLET VALVE, SAID FUEL CHAMBER BEING UNVENTED EXCEPT THROUGH THE MIXING PASSAGE, AND AN AIR BLEED CHANNEL FORMED IN SAID BODY MEMBER BETWEEN THE PASSABE MEANS AND THE MIXING PASSAGE AND OPENING INTO SAID MIXING PASSAGE AT THE AIR INLET REGION THEREOF FOR CONVEYING AIR INTO THE FUEL PRIOR TO ITS DELIVERY THROUGHT THE ORIFICE INTO THE MIXING PASSAGE. 